This application relates to a self-actuated bleed valve for assisting start-up of a gas turbine engine.
Gas turbine engines are provided with a number of functional sections, including a fan section, a compressor section, a combustion section, and a turbine section. Air and fuel are combusted in the combustion section. The products of the combustion move downstream, and pass over a series of turbine rotors, driving the rotors to provide power. The turbines drive the compressor and fan rotors.
At start-up, the turbine section of the gas turbine engine has not begun to fully provide power. Thus, driving the compressor, as an example, is more challenging than it will be at steady state conditions. It is known in prior art gas turbine engines to include a bleed valve to bleed air away from the compressor section during start-up and reduce the load to drive the compressor. Known bleed valves utilize some form of electric, pneumatic or hydraulic actuator to drive a valve between open and closed positions. The valve is powered open at start-up and powered to a closed position after start-up has been completed.
The powered valves are somewhat expensive and complex.